Scientific Theory or Model

for Prof. Smoot's Physics 10 class

A scientific theory is a synthesis of well-tested and verified hypotheses about some aspect of he world around us. When a scientific hypothesis has been confirmed repeated by experiment, it may become known as a scientific law or scientific principle. A scientific fact may be defined as an agreement by competent observers of a series of observations of the same phenomena. From time to time scientific facts are revised by additional data about the world around us. Scientists often employ a model in order to understand a particular set of phenomena. A model is a mental image of the phenomena using terms (or images) with which we are familar. For example, in the planetary model of the atom scientists visualize the atom as a nucleus with electrons orbiting around it in a manner similar to the way that planets revolve around the Sun. While this model is useul in understanding the atom, it is an over-simplified description of a real atom and does not describe/predict all of its attributes.

A particular feature of science is that it is continually evolving as a result of the The Scientific Method which calls for a constant testing of ideas and observations of scientific facts and theories/models. In order for science to evolve previously accepted theories (PATs) must be superceded by new theories (NTs). Since it is relatively easy to make up new theories, particularly if one is unencumbered by observations, there must be criteria for the replacement of previously accepted theories by the new theories.

Criteria is the plural of criterion. a criterion is a standard of judgement. A particularly good example is the Ms. Universe (or other beauty) contest where the criteria are well spelled out and the procedures to reaching a final choice are well-defined.

Here are five criteria that are generally used when comparing theories and a new theory statisfying these will then replace a previously accepted theory.

I. The previously accepted theory gave an acceptable explanation of something, the new theory must give the same results.
II. New theory explains something that the PAT either got wrong or, more commonly, did not apply.
III. Makes a prediction that is later verified.
IV. Elegance - Aesthetic quality - simple, powerful includes universal symmetries. That is simple, easy-to-remember or apply formulation, experssed as some symmetry of nature, be powerful enough to used in many applications
V. Provide a deeper insight or link to another branch of knowledge

To be accepted the more of these criteria that are satisfied the better.